Dr. Jan Skapa Profile

Dr. Jan Skapa

Assistant Proffessor at VŠB-Technical Univ. of Ostrava

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Publications (21)

Proceedings Article | 14 May 2018 Paper

FBG strain sensor mounted on plastic carrier

Marcel Fajkus, Jan Nedoma, Pavel Mec, Jan Jargus, Lucie Svobodova, Jan Skapa, Radek Martinek, Vladimir Vasinek

Proceedings Volume 10654, 1065416 (2018) https://doi.org/10.1117/12.2304933

KEYWORDS: Sensors, Fiber Bragg gratings, Bragg gratings, 3D printing, Adhesives, Metals, Mathematical modeling, Optical fibers, Fiber optics sensors, Telecommunications

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Proceedings Article | 12 May 2016 Paper

Optimization of multilayer neural network parameters for speaker recognition

Jaromir Tovarek, Pavol Partila, Jan Rozhon, Miroslav Voznak, Jan Skapa, Dominik Uhrin, Zdenka Chmelikova

Proceedings Volume 9850, 98500C (2016) https://doi.org/10.1117/12.2223545

KEYWORDS: Neural networks, Databases, Neurons, Speaker recognition, Biometrics, Signal processing, Forensic science, Systems modeling, Vestigial sideband modulation, Genetics

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Proceedings Article | 25 September 2013 Paper

Recovery of LED diode optical spectrum

Jan Vitasek, Jan Latal, Petr Siska, Jan Skapa, Martin Papes, Vladimir Vasinek

Proceedings Volume 8874, 88740M (2013) https://doi.org/10.1117/12.2023862

KEYWORDS: Light emitting diodes, Diodes, Modulation, Free space optics, Visible radiation, Networks, Radium, Optical components, Ocean optics, Standards development

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Proceedings Article | 11 May 2012 Paper

Simulation of the influence of atmospheric conditions on low-cost optical free space link

Jan Latal, Petr Koudelka, Jan Vitasek, Petr Siska, Jan Skapa, Andrej Liner, Martin Papes, Vladimir Vasinek

Proceedings Volume 8433, 84331T (2012) https://doi.org/10.1117/12.921700

KEYWORDS: Free space optics, Atmospheric optics, Free space, Eye, Photodetectors, Optical amplifiers, Signal attenuation, Semiconductor lasers, Fiber optic gyroscopes, Photodiodes

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Proceedings Article | 2 May 2012 Paper

The design of equipment for optical power measurement in FSO link beam cross-section

Jan Latal, Tomas David, Otakar Wilfert, Zdenek Kolka, Petr Koudelka, Frantisek Hanacek, Jan Vitasek, Petr Siska, Jan Skapa, Vladimir Vasinek

Proceedings Volume 8436, 843610 (2012) https://doi.org/10.1117/12.921701

KEYWORDS: Free space optics, Atmospheric optics, Optical testing, Measurement devices, Control systems, Free space, Radio optics, Head, Connectors, Sensors

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Proceedings Article | 9 May 2011 Paper

Fiber optic DTS system application in the research of accumulation possibilities of thermal energy in the rock mass

Jan Látal, Petr Koudelka, Petr Šiška, Jan Skapa, František Hanáečk, Vladimír Vašinek, Jan Vitásek, Stanislav Hejduk, Jiří Bocheza

Proceedings Volume 8073, 80731T (2011) https://doi.org/10.1117/12.887082

KEYWORDS: Temperature metrology, Fiber optics, Sensors, Raman scattering, Optical fibers, Temperature sensors, Optical sensors, Vestigial sideband modulation, Molecules, Electrical engineering

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Proceedings Article | 9 May 2011 Paper

Measurement of the spectral characteristics of telecommunication fiber emitted at high temperatures

F. Hanacek, J. Latal, P. Koudelka, P. Siska, J. Skapa, J. Vitásek, V. Vasinek, J. Hurta

Proceedings Volume 8073, 80731V (2011) https://doi.org/10.1117/12.887093

KEYWORDS: Optical fibers, Temperature metrology, Telecommunications, Multimode fibers, Fiber characterization, Sensors, Black bodies, Fiber optics sensors, Waveguides, Spectrometers

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Proceedings Article | 23 February 2011 Paper

Passive fiber ring as a device for effective refractive index measurement

Vladimir Vasinek, Jan Látal, Petr Koudelka, Petr Šiška, František Hanáček, Jan Skapa

Proceedings Volume 7934, 79341J (2011) https://doi.org/10.1117/12.875316

KEYWORDS: Refractive index, Fiber lasers, Signal attenuation, Fiber amplifiers, Fiber optics, Oscillators, Single mode fibers, Superposition, Feedback loops, Optical fibers

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Proceedings Article | 28 October 2010 Paper

Mach-Zehnder fiber interferometer for people monitoring

Vladimir Vasinek, Jan Latal, Petr Koudelka, Petr Siska, Jan Vitasek, Jan Skapa

Proceedings Volume 7833, 78330Y (2010) https://doi.org/10.1117/12.864870

KEYWORDS: Interferometers, Signal processing, Mach-Zehnder interferometers, Interferometry, Optical fibers, Fourier transforms, Motion analysis, Single mode fibers, Sensors, Fiber couplers

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Fiber optical interferometers belong to highly sensitive equipments that are able to measure slight changes like distortion of shape, temperature and electric field variation and etc. Their great advantage is that they are insensitive on ageing component, from which they are composed of. It is in virtue of herewith, that there are evaluated no changes in optical signal intensity but number interference fringes. To monitor the movement of persons, eventually to analyze the changes in state of motion we developed method based on analysis the dynamic changes in interferometric pattern. We have used Mach- Zehnder interferometer with conventional SM fibers excited with the DFB laser at wavelength of 1550 nm. It was terminated with optical receiver containing InGaAs PIN photodiode. Its output was brought into measuring card module that performs on FFT of the received interferometer signal. The signal rises with the composition of two waves passing through single interferometer arm. The optical fiber SMF 28e in one arm is referential; the second one is positioned on measuring slab at dimensions of 1x2m. A movement of persons over the slab was monitored, signal processed with FFT and frequency spectra were evaluated. They rose owing to dynamic changes of interferometric pattern. The results reflect that the individual subjects passing through slab embody characteristic frequency spectra, which are individual for particular persons. The scope of measuring frequencies proceeded from zero to 10 KHz. It was also displayed in experiments that the experimental subjects, who walked around the slab and at the same time they have had changed their state of motion (knee joint fixation), embodied characteristic changes in their frequency spectra. At experiments the stability of interferometric patterns was evaluated as from time aspects, so from the view of repeated identical experiments. Two kinds of balls (tennis and ping-pong) were used to plot the repeatability measurements and the gained spectra at repeated drops of balls were compared. Those stroked upon the same place and from the same elevation and dispersion of the obtained frequency spectra was evaluated. These experiments were performed on the series of 20 repeated drops from highs of 0,5 and 1m. The evaluation of experiments displayed that the dispersion of measured values is lower than 4%.

Proceedings Article | 18 August 2010 Paper

Changes in optical spectrum of photonic fiber with two counter propagating laser beams

Vladimir Vasinek, Jan Latal, Petr Koudelka, Petr Siska, Frantisek Hanacek, Jan Skapa

Proceedings Volume 7781, 77810Y (2010) https://doi.org/10.1117/12.860219

KEYWORDS: Photonic crystal fibers, Semiconductor lasers, Fiber lasers, Signal attenuation, Fiber couplers, Mirrors, Laser beam propagation, Structured optical fibers, Resonators, Optical fibers

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Proceedings Article | 14 May 2010 Paper

Optical fiber distributed temperature sensor in cardiological surgeries

Jan Skapa, Jan Látal, Marek Penhaker, Petr Koudelka, František Hancek, Vladimír Vasinek

Proceedings Volume 7726, 77261V (2010) https://doi.org/10.1117/12.854309

KEYWORDS: Optical fibers, Temperature metrology, Raman scattering, Surgery, Molecules, Scattering, Temperature sensors, Rayleigh scattering, Sensors, Raman spectroscopy

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Proceedings Article | 26 February 2010 Paper

Passive fiber rings as a basic part of fiber optic sensors

Jan Látal, Petr Koudelka, Petr Šiška, František Hanáček, Jan Skapa, Vladimír Vašinek

Proceedings Volume 7597, 75971W (2010) https://doi.org/10.1117/12.837815

KEYWORDS: Fiber optics sensors, Fiber amplifiers, Refractive index, Fiber lasers, Signal attenuation, Feedback loops, Fiber optics, Superposition, Erbium, Amplifiers

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Proceedings Article | 5 June 2009 Open Access

From university to company: education of optical communications in cooperation with industry at Technical University of Ostrava

Vladimir Vasinek, Jan Skapa, Petr Siska, Frantisek Hanacek, Jan Latal, Petr Koudelka, Iva Petrikova

Proceedings Volume 9666, 96660Y (2009) https://doi.org/10.1117/12.2208030

KEYWORDS: Structured optical fibers, Atmospheric optics, Active optics, Biomedical optics, Geometrical optics, Thermography, Optical fibers, Dispersion, Telecommunications, Optical communications

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Proceedings Article | 18 May 2009 Paper

Optical fiber sensor based on redistribution of power among several guided modes

Petr Siska, Jan Skapa, Vladimir Vasinek, Frantisek Hanacek, Ivan Kasik

Proceedings Volume 7356, 73561Y (2009) https://doi.org/10.1117/12.820713

KEYWORDS: Optical fibers, Fiber optics sensors, Refractive index, Wave propagation, Sensors, Optical design, Telecommunications, Single mode fibers, Structured optical fibers, Structural design

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Proceedings Article | 18 May 2009 Paper

Novel optical-fiber structure as a tension sensor

J. Skapa, P. Siska, V. Vasinek, J. Vanda

Proceedings Volume 7356, 73561G (2009) https://doi.org/10.1117/12.820547

KEYWORDS: Optical fibers, Sensors, Telecommunications, Refractive index, Signal attenuation, Optical sensors, Fiber optics sensors, Single mode fibers, Temperature metrology, Optical design

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Proceedings Article | 20 November 2008 Paper

Novel multifunctional structures based on redistribution of optical power as basis for fiber optic sensors

Petr Šiška, Jan Skapa, Vladimír Vašinek, Ivan Kašík, Vlastimil Matějec

Proceedings Volume 7141, 71410H (2008) https://doi.org/10.1117/12.822362

KEYWORDS: Optical fibers, Fiber optics sensors, Refractive index, Wavelets, Sensors, Waveguides, Telecommunications, Cameras, Single mode fibers, Optical testing

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Sensors built with the help of optical fibers can measure almost all magnitudes in these days [3]. In our research we design new novel multifunctional structures that afford concurrently utilizing of optical fiber for telecommunications and measurements. These fibers are designed to work on two wavelengths. On telecommunication wavelength of 1550 nm these fibers are operating in single mode regime and on measurement wavelength of 850 nm they are working in quasisingle mode regime. Complicated profiles of refractive indexes provide four LP modes on 850 nm that are supported by fibers and that transmit a significant amount of power. First samples of these hybrid fibers have already been made thanks to grant cooperation with Academy of Science of Czech Republic. These refractive index profiles have to be designed in such way that all supported modes should carry approximate the same amount of optical power. The usage of both wavelength means that the light of communication wavelength must not be affected by the fiber activities at the wavelength of 850nm. The consequence is that only redistribution of optical power among supported modes can be applied. The Fourier and wavelet analysis is used to find out the significant points in the progression of the optical power. There are changes in the Fourier spectra and changes in wavelet coefficients. From the Fourier analysis we can predict the progression; wavelet analysis [2] enables us to find out singularities. It is expected, that every change on the fiber has its own "fingerprint" in the redistribution of the optical power. The main instrument is the coupled mode equations [1] following directly from the wave equations for individual modes. They contain a detailed description of the phase and amplitude of all the modes at any point z along the waveguide. But usually we are not interested in the phases and amplitudes of the individual modes. For the most of practical intentions, it is sufficient to know the average of the amount of power carried by each mode. Coupled power equations for the average mode power are derived for weak coupling between modes. It means that coupling requires a distance of 1000 wavelengths for a complete exchange of power between two modes. It is a set of finite number of first-order differential equations with symmetric constant coefficients. Coupling to forward traveling guided modes occurs for distortion function f(z) whose Fourier spectra are limited to spatial frequencies. In the contribution refractive index profiles will be presented together with first camera photos analysis of such fiber temperature sensor. Temperature crosstalk to communication wavelength of 1550nm will be also specified.

Proceedings Article | 28 April 2008 Paper

Identification of external quantities using redistribution of optical power

Jan Skapa, Petr Siska, Vladimír Vasinek, Jan Vanda

Proceedings Volume 7003, 70031R (2008) https://doi.org/10.1117/12.780935

KEYWORDS: Optical fibers, Signal attenuation, Data transmission, Sensors, Single mode fibers, Spatial light modulators, Telecommunications, Refractive index, Manufacturing, Diffraction

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Proceedings Article | 12 October 2007 Paper

Analysis of optical-power redistribution for hybrid optical fibers

J. Skapa, V. Vašinek, P. Šiška

Proceedings Volume 6770, 67701B (2007) https://doi.org/10.1117/12.752587

KEYWORDS: Wavelets, Optical fibers, Telecommunications, Hybrid optics, Spatial light modulators, Diffraction, Fiber optics sensors, Microscopes, Cameras, Waveguides

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Proceedings Article | 10 September 2007 Paper

Static and dynamic reflection coefficients of the wall surfaces and their influence on optical power distribution in fibreless diffused networks

Vladimir Vasinek, Jaromir Necesany, Jan Skapa, David Dubcak, Pavel Nevlud

Proceedings Volume 6775, 67750T (2007) https://doi.org/10.1117/12.734219

KEYWORDS: Reflection, Reflectivity, Geometrical optics, Absorption, Bidirectional reflectance transmission function, Light, Mathematical modeling, Spatial frequencies, Optical networks, Systems modeling

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Proceedings Article | 17 May 2007 Paper

Nonlinear effects in microstructured polymer optical fibres

Jan Vanda, Jaromir Necesany, Jan Skapa, Vladimir Vasinek, Alex Argyros, Martijn van Eijkelenborg, Maryanne Large

Proceedings Volume 6588, 65880R (2007) https://doi.org/10.1117/12.722367

KEYWORDS: Signal attenuation, Optical fibers, Polymers, Polymethylmethacrylate, Nonlinear optics, Refractive index, Photonic crystal fibers, Silica, Glucose, Structured optical fibers

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Proceedings Article | 16 May 2007 Paper

Mode visualization for fiber optic temperature sensor

Vladimir Vasinek, Petr Siska, Leos Marsalek, Jan Skapa

Proceedings Volume 6585, 65851U (2007) https://doi.org/10.1117/12.722881

KEYWORDS: Optical fibers, Signal attenuation, Fiber optics sensors, Near field optics, Single mode fibers, Fiber optic communications, Fiber optics, Temperature sensors, Telecommunications, Temperature metrology

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Showing 5 of 21 publications

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